Abstract: The spore of Camptosorus sibiricus is bilateral and monoleta. with a prominent perine. The patterns of spore gemination is of Vittaria-type (Nayar & Kaur 1971). The germ filaments develop 2-7 cells long, uniseriate or multiseriate. The prothallial development is of the Aspidium-type (Nayar & Kaur 1971). The prothalli are cordate and hairy with median light midrib. The form of hair isvaried. The sex organs are rather small. The antheridial dehiscence is by pore-like opening developed in the cap cell. The neck of archegonia are slander. As mentioned above, the characteristics of Camptosorus sibiricus on the development of the gametophytes are common in a advanced fern type. It is similar with thegametophyte of Phyllitis japonica in the main characters. It seems that they would be at closed phylogeny level in the family Aspleniaceae.

Key words: Gametophytes, Aspleniaceae, Northeast of China